A DSP-based lattice-pole-zero acoustic ECHO canceller

Abstract

In this paper, a practical pole-zero lattice adaptive acoustic echo canceller (AEC) for hands-free telephone is proposed. The proposed algorithm consists in two parts: forward lattice and inverse lattice. Collectively, they are referred to as LATIN (Lattice and Inverse Lattice) configuration. While the forward lattice is responsible for acoustic echo cancellation, the inverse lattice is employed in the double-talk (DT) mode only as to undo the distortion of the near-end speech brought about by the forward lattice filter when suppressing the acoustic echo. Assuming M poles and M zeros for the proposed AEC, the complexity of the proposed algorithm is approximately twice the complexity of an M-tap FIR gradient lattice algorithm. Real-time experimentation conducted on a floating-point DSP chip and simulation results attest to the stability, fast convergence, and high acoustic echo suppression of the proposed pole-zero algorithm.